Cang Tao, Diao Ziyang, Di Shanshan, Liu Zhenzhen, Wang Zhiwei, Zhao Huiyu, Xu Hao, Zhang Chenghui, Qi Peipei, Wang Xinquan
State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang, Institute of Quality and Standard of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, PR China; Agricultural Ministry Key Laboratory for Pesticide Residue Detection, Hangzhou 310021, PR China.
State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang, Institute of Quality and Standard of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, PR China; Agricultural Ministry Key Laboratory for Pesticide Residue Detection, Hangzhou 310021, PR China; College of Food Science & Engineering, Hainan University, No. 158 Renmin Avenue, Haikou, 570100, PR China.
Sci Total Environ. 2022 Dec 15;852:158472. doi: 10.1016/j.scitotenv.2022.158472. Epub 2022 Sep 6.
Pyrisoxazole is a chiral fungicide with high sterilizing activity to the plant pathogenic bacteria. It has two chiral C atoms, which bring four stereoisomers. The present work was the first time to explore the stereoselective bioaccumulation behavior of pyrisoxazole in earthworms by chiral liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS). The absolute configurations of pyrisoxazole stereoisomers were confirmed by circular dichroism (CD) coupled with calculated electronic circular dichroism (ECD) method, and the elution order in Lux Cellulose-3 column was as follows: (-)-3S, 5R-pyrisoxazole, (+)-3R, 5S-pyrisoxazole, (+)-3S, 5S-pyrisoxazole and (-)-3R, 5R-pyrisoxazole. The recoveries of pyrisoxazole stereoisomers in earthworm and soil samples ranged from 80.8 % to 101 % with the RSD lower than 6.3 %. In bioaccumulation progress, (+)-3R, 5S-pyrisoxazole was accumulated preferentially in earthworms, and the bioaccumulation concentrations of high-activity (-)-3S, 5R-pyrisoxazole were the lowest. There were no stereoselective bioaccumulation between (+)-3S, 5S-pyrisoxazole and (-)-3R, 5R-pyrisoxazole, while there was diastereoselectivity between Z-pyrisoxazole and E-pyrisoxazole with higher E-pyrisoxazole concentrations. In the whole bioaccumulation process, the BAF values of (+)-3R, 5S-pyrisoxazole were significantly higher than (-)-3S, 5R-pyrisoxazole, and the BAF values of (-)-3S, 5R-pyrisoxazole were the lowest. The dissipation of pyrisoxazole stereoisomers in the artificial soil was very slow and had no stereoselectivity, and the existence of earthworms had little effects on the dissipation of pyrisoxazole stereoisomers, which indicated that the stereoselective behaviors of pyrisoxazole in earthworms were caused by the stereoselective enrichment and dissipation of earthworms themselves. Taken together, (-)-3S, 5R-pyrisoxazole was recommend as a commercial product. This study played a positive role in guiding the development of environmentally friendly pesticides and provided database for the environmental and biological risk assessment of pyrisoxazole.
吡唑醚菌酯是一种对植物病原菌具有高杀菌活性的手性杀菌剂。它有两个手性碳原子，产生四种立体异构体。本研究首次采用手性液相色谱-四极杆飞行时间质谱联用技术（LC-Q-TOF/MS），研究吡唑醚菌酯在蚯蚓体内的立体选择性生物累积行为。通过圆二色光谱（CD）结合计算电子圆二色光谱（ECD）方法确定了吡唑醚菌酯立体异构体的绝对构型，其在Lux Cellulose-3色谱柱上的洗脱顺序为：（-）-3S, 5R-吡唑醚菌酯、（+）-3R, 5S-吡唑醚菌酯、（+）-3S, 5S-吡唑醚菌酯和（-）-3R, 5R-吡唑醚菌酯。吡唑醚菌酯立体异构体在蚯蚓和土壤样品中的回收率在80.8%至101%之间，相对标准偏差低于6.3%。在生物累积过程中，（+）-3R, 5S-吡唑醚菌酯优先在蚯蚓体内累积，高活性的（-）-3S, 5R-吡唑醚菌酯生物累积浓度最低。（+）-3S, 5S-吡唑醚菌酯和（-）-3R, 5R-吡唑醚菌酯之间不存在立体选择性生物累积，而Z-吡唑醚菌酯和E-吡唑醚菌酯之间存在非对映选择性，E-吡唑醚菌酯浓度较高。在整个生物累积过程中，（+）-3R, 5S-吡唑醚菌酯的生物累积因子（BAF）值显著高于（-）-3S, 5R-吡唑醚菌酯，（-）-3S, 5R-吡唑醚菌酯的BAF值最低。吡唑醚菌酯立体异构体在人工土壤中的降解非常缓慢且无立体选择性，蚯蚓的存在对吡唑醚菌酯立体异构体的降解影响很小，这表明吡唑醚菌酯在蚯蚓体内的立体选择性行为是由蚯蚓自身的立体选择性富集和降解引起的。综上所述，推荐（-）-3S, 5R-吡唑醚菌酯作为商业产品。本研究对指导环境友好型农药的开发具有积极作用，并为吡唑醚菌酯的环境和生物风险评估提供了数据库。
